1. Field of the Invention
The present invention relates to a cleaning method and a cleaning apparatus, and more particularly relates to a cleaning method and a cleaning apparatus which are capable of peeling off and removing a photoresist or the like at room temperatures.
2. Description of the Related Art
Conventionally, in the wet processes of semiconductor or liquid crystal display manufacture, the peeling off of the resist was conducted by mixing sulfuric acid and an aqueous hydrogen peroxide solution and conducting high temperature treatment within a range of 100.degree.-150.degree. C. Alternatively, methods were employed in which, after treatment at high temperatures with an organic solvent at a high concentration, the organic solvent deposited on the substrate was further treated by means of a different organic solvent. Furthermore, when ion implantation or reactive ion etching is conducted using the photoresist as a mask, large amounts of ions are irradiated onto the resist surface, and the resist material itself is essentially carbonized, so that removal can not be conducted by means of chemicals, and thus a method is introduced in which plasma treatment is conducted by means of an oxygen plasma or by means of UV rays and ozone gas, and after the carbonized portions of the resist have been removed by incineration; the remainder of the resist is removed by chemicals.
However, the method in which sulfuric acid or hydrogen peroxide is employed has many defects, in that the operability of the cleaning fluid and silicon wafer conveyance is poor because the treatment is conducted at high temperatures, and furthermore, since the hydrogen peroxide in the cleaning liquid breaks down, there is difficulty in the management of the fluid, so that chemical and water vapors are generated in large amounts and large amounts of clean air are required for the removal thereof, and scrubbers are necessary for the removal of the chemical vapors from the exhaust air, and the like, so that the costs both in terms of power consumption and machinery are high, and there are costs involved with the treatment of the sulfuric acid waste liquid.
The method in which organic solvents are employed also has poor operability, since it is also conducted at high temperatures, and the treatment of waste liquid is also troublesome. Whether treatment is conducted by means of sulfuric acid and hydrogen peroxide or by means of organic solvents, the peeling mechanism does not involve the peeling of the resist, but rather the dissolving of the resist. Since the resist on the substrate surfaces of the semiconductor and the like; which is applied on all surfaces to a depth of 1-2 .mu.m, is completely dissolved, the degradation of the peeling agent is extremely severe.
The plasma treatment method has problems in that after treatment, contaminants contained in the resist, such as metals and microgranules and the like, remain on the wafer.